Size-dependent elastic properties of single-walled ZnO nanotubes: A first-principles study

By means of first-principles calculations, we have investigated a size dependence of elastic modulus in single-walled ZnO nanotubes with armchair and zigzag forms. It is found that for these tubes the Young's modulus is increased dramatically with the increased diameters and inversely proportional to the Zn-O bond length. Further, the amount of charge transfer, calculated by the Bader analysis, is introduced to elucidate the strength of bonding between Zn and O atoms in these tubes.